Blade for propellers, ventilating fans, and the like



March 112, 19296 A. CERFVQL BLADE FOR PROPELLERS, VENTILATING FANS, AND THE LIKE Original Filed July 23, 1926 Patented Mar. 12, 1929.

UNITED STATES PATENT OFFICE.

ALBERT CERFVOL, OF BARKIN G, ENGLAND, ASSIGNOR 013 ON E-FIFI'H TO JOHN ALEX- ANDEB FISHER, ONE-FIFTH TO FREDERICK WILLIAM SHEARS, ONE-FIFTH T ED- WABD LUMSDEN AND ONE-FIFTH T0 CHARLES RAYMOND, ALL OF LONDON, ENG- LAND.

BLADE FOR PROPELLERS, VENTILATING FANS, AND THE LIKE.

Original application The object of this invention is to construct a blade for air propellers, ventilating fans and the like, whereby perfect flexibihty is maintained along the entire length of the blade under all working conditions, thereby materially increasing the efficiency of Working of such a blade, this application being a division of application Serial No. 124,497, filed July 23 1926, now U. S. Patent No. 1,661,921, 1ssued March 6, 1928.

According to this invention the blade is composed of a foundation of a multiple of tapered springy rods secured at the desired distances apart to a rigid support which is connected to a carrying boss secured to the driving shaft.

These rods are formed slightly fan shaped andare connected together at their free or smaller ends by suitable flexible or other con nections, the Whole or a greater part of such rods being covered by a mult1ple of metal plates each engaging opposite rods by means of curled edges which function as clips so as to allow each rod certain movement individ 2 uall'y or collectively and returning or allowing each rod to return to its normal position.

It is preferred that the blade and its boss be connected to the driving shaft by spring controlled means to which there is an imaginary or positive hinged line running parallel with the axis of rotation; that is to say, if the bosses carrying the blades are connected direct to the driving shaft through springy or flexible means, or the boss can be hinged to the means on the shaft, in which case the action of the blades is further controlled by springs,

' and in both cases each blade is given a slight oscillatory movement about its mean position, in addition to which the action of the air dur- 40 ing revolution of the blades acts on said blades to cause them to adapt themselves in surface condition to obtain proper action against the air and thus more efliciency in action. The invention will be more particularly understood from the following description taken in connection with the accompanying drawin in which:

igure .1 is a plan of ablade in which the rods are connected by plates loosely-connectfiled .Tulyv23, 1926, serial No. 124,497, and in Great Britain July 7, 1926. Divided and this application filed December 5, 1927. Serial No.

Figure 4 is a plan view of a complete propeller with spring means or connection to the driving shaft.

According to this construction four tapered sprlngy rods 1 preferably of springy steel are employed, and these are screw threaded at their thicker ends and screwed into holes 1n a support 2, the rods 1 being positioned slightly fan shaped. In the preferred application to the driving shaft 3, each support is connected to a bell crank lever 4 pivoted to an arm 5 of a boss 6' secured to the shaft 3, the free arm of the bell crank lever 4 being pivotally connected by springs 7 to another arm 5 of the boss 6, as will be understood from Figure 4.

Each bell crank lever 4 is screwed into the support 2, in the construction shown the end rod 1 being screwed into the bell crank lever 4 and the two arms clamped in the split end of the support 2 by bolt and nut 8.

At some little distance from the support 2 and embracing the rod is what might be termed a flexible stiffener, i. e. two strips of India rubber 9, 9, (See Figure 3) embracing the rods and held thereto by rivets 10 passed between the rods 1. I

The free and smaller ends of the rods 1 are connected together by links 14, these being loosely attached to allow of an individual or r I collective movement of the rods 1, and from, just beyond the stiffener 9 the remainder of the blade, including the links, is covered on one side by metal plates 17, each having curled edges 17 a as clips for loosely engaging the rods such clips being positioned so that the plates,

- when positioned in one plane, will form a com plete surface to one side of the blade.

What I do claim as my invention and desire to obtain by Letters Patent is 1. A blade for propellers, ventilating fans and the like comprising three or more tapered spring rods each rigidlyheld at their thicker i ends to a support attachable to the driving shaft and arranged fan shaped, and a covering on one side of the rods, said covering comprising metal plates having clips engaging the rods for loosely retaining them together.

2. A blade for propellers, ventilating fans and the like comprising a series of tapered spring rods held at their thicker ends to a support attachable to the driving shaft and arranged fan shaped, and a covering on one side of the rods, said covering comprising metal plates having clips engaging the rods for loosely retaining them together, the thinner ends of the rods being loosely connected together.

3. The herein-described blade including a support, a plurality of tapered rods, the thicker ends of which are anchored in the support in spaced relation to ech other, means for flexibly connecting the free ends of the rods serially, and a plurality of metal plates flexibly connected to the rods and formin a covering upon one side of the rod, each of said plates being provided at its longitudinal edges with rod receptacles and adjacent plates having intel-fitting recesses and projections along their longitudinal meeting edges.

In testimony whereof I have hereunto set my hand.

ALBERT CERFVOL. 

